TAMRON AF 18-270mm f/3.5-6.3 Di II VC LD Aspherical (IF) MACRO for DSLR

The latest design to emerge from the stable of superzoom experts Tamron, the AF 18-270mm f/3.5-6.3 Di II VC LD Aspherical (IF) MACRO was announced in July 2008. The length of the zoom range is almost as remarkable as that of the lens's name itself, with the 15x ratio covering everything from a 28mm equivalent wideangle to a 420mm equivalent telephoto. This is unprecedented in terms of SLR optics, and is clearly aimed at users upgrading from superzoom digicams who require a similar focal length range without the inconvenience of changing lenses.

It also makes a compelling option as an all-in-one travel/'walkabout' solution. A minimum focus distance of just 0.5m throughout the zoom range, and the incorporation of optical image stabilization (or 'Vibration Compensation' as Tamron call it) enhance the lens's flexibility still further. It is available only in mounts for Canon and Nikon DSLRs; presumably Pentax and Sony owners will continue to be served by Tamron's existing 18-250mm F3.5-6.3, with image stabilization provided by the camera body.

Making a lens with such an extraordinary range is always gong to require some pretty clever engineering, and Tamron's design team have clearly been burning the midnight oil on this one. The optical formula features no fewer than 18 elements in 13 groups, including three aspherical elements and two Low Dispersion (LD) glass elements for the control of aberrations. A 'double-trombone' mechanical design allows the lens almost to double in length between 18mm and 270mm, whilst keeping the overall size and weight very similar to competing 18-200mm lenses.

The 18-270mm F3.5-6.3 VC will compete head-to-head in the 'stabilized superzoom' market with the Canon EF-S 18-200mm F3.5-5.6 IS, Nikon 18-200mm f/3.5-5.6G IF-ED AF-S VR DX, and Sigma 18-200mm F3.5-6.3 DC OS, but offering the benefit of substantially extended telephoto range. Tamron hails it as 'The Ultimate All-In-One Zoom: Longest, Steadiest Lens On Earth', and while it seems likely that this phrase may have lost something in translation, it does give a good impression the lens's appeal. But can such a general-purpose optic actually be any good?

Headline features

• 27-405mm equivalent focal length range; F3.5-6.3 maximum aperture
• Vibration Compensation (VC) optical image stabilisation (up to 4 stops)
• Available for Canon EF mount and Nikon F mount (APS-C/DX format DSLRs only)

Angle of view

The pictures below illustrate the (frankly extraordinary) focal length range from wide to telephoto (on Nikon DX format, 1.5x).

18mm (27mm equivalent)

http://www.dpreview.com/lensreviews/tamron_18-270_3p5-6p3_vc_n15/